Effect of beta-lactamase inhibitors on beta-lactamases from anaerobic bacteria

Three beta-lactamase inhibitors in clinical use — clavulanic acid, sulbactam and tazobactam — were investigated for their activity on beta-lactamases fromBacteroides uniformis, Clostridium butyricum andFusobacterium nucleatum. Purification of the beta-lactamases was carried out by anion-exchange chromatography, gel filtration and FPLC. The inactivation of beta-lactamase activity was determined spectrophotometrically with nitrocefin as substrate. Various concentrations of the inhibitors were preincubated at 30 °C together with the enzyme for different periods of time before determination of the beta-lactamase activity. The three beta-lactamases tested were more susceptible to tazobactam than to clavulanic acid and sulbactam. Clavulanic acid and sulbactam reduced the enzyme activity of theBacteroides uniformis beta-lactamase more effectively than theClostridium butyricum andFusobacterium nucleatum beta-lactamases.